Semiconductor and micromechanical dies or chips are frequently packaged for protection against an external environment. The package provides physical protection, stability, external connections, and in some cases, cooling to the die inside the packages. Typically the chip or die is attached to a substrate and then a cover that attaches to the substrate is placed over the die. Alternatively, the die is attached to a cover and then a package substrate is formed on the die.
There is a trend to add more functions to each die and to put more than one die in a single package. This causes the packages to be larger and also increases specialization for packages. While a very high volume product, such as a cellular telephone may benefit from highly specialized purpose built components, a low volume product does not. For lower volume and more specialized products, it may be less expensive to select from multiple existing smaller dies. This allows more flexibility in the functions provided for the product and allows the product to use smaller packaged dies.
Current packaging technologies use rigid pre-impregnated fiberglass or silicon to carry different dies and to connect the dies to each other. This provides a stable platform to hold the dies and for the wiring layers used by the dies. However, a rigid substrate requires a wide, flat, and rigid location to be mounted in a device. As the Internet of Things, further automation, and connectivity expand, microelectronics are desired for a wider variety of different things. These microelectronic applications may include clothing, writing accessories medical devices, and a wide range of small pocketable and wearable things. Many such things do not provide a wide, flat, rigid location for a device package.